Brushless motors schematically comprise a casing closed by a cap to form a housing in which there is a wound stator and a rotor with permanent magnets.
Brushless motors are also equipped with control electronics which control their operation and can be positioned inside or outside the above-mentioned housing.
One type of motor, called the open type, has apertures on the casing which allow the circulation of air for cooling the stator windings.
The market requires motors or open motors, that is to say, motors which are easy to cool, but which are equipped with sealed electronics, so as to obtain a product which is more reliable since the electronic components are protected from outside agents.
Usually, the motors of the type described are designed for driving fans in electric ventilators for cooling radiant masses.
In these applications in particular, the electric ventilators are supported by a fan duct using the motor casing; more specifically, in numerous prior art solutions, the fan duct of the electric ventilator comprises a ring for mounting the motor the casing of which is equipped with protrusions for coupling with the ring.
In an example prior art solution the electronic circuits are located inside a housing which is sealed closed and which is, in turn, positioned inside the motor. More precisely, in the prior art solutions, the housing which encloses the electronics is located in the motor cap inside the motor and the board inside it is connected to the stator by connectors, for example faston connectors.
These latter solutions are not free of disadvantages.
The closing cap must be oversized in order to be able to receive inside it a closed housing incorporating the control electronics.
The electronics are very close to the stator windings and in the same environment and therefore may be affected by the temperature increase caused by motor operation.
Moreover, the connection of the stator windings to the printed circuit board is made by means of connectors and is easily subject to reliability and efficiency problems due to, for example, vibrations or wear on the contact itself.
The fan duct must have the mounting ring and the coupling with the respective electric ventilator is relatively complex.
In particular applications, the coupling of the motor with the corresponding fan duct or with a diffuser for diffusing the flow generated by the fan is unsatisfactory from a fluid dynamic point of view.